Long before diabetes, cervical cancer and other diseases are diagnosed, people often live for years on the borderline, with the condition yet to take hold. This period is a pivotal time, in which making lifestyle changes can actually slow down the progression of the "real" problem or even reverse the pre-condition altogether. However, most pre-diseases do not have noticeable symptoms, so unless you are tested for them, you may not even realize you're crossing the line. Read on to discover the precursors of five common health problems, and learn what you can do to prevent—or minimize—your chances of developing them.

Prehypertension

What it is: Prehypertension, also known as borderline high bloodpressure, is marked by having a blood pressure between 120/80 mmHg and 139/89 mmHg, compared to a normal blood pressure, which is less than 120 mmHG over less than 80 mmHg (for more information about understanding blood pressure, click here to visit the AmericanHeartAssociation's website). In general, there are no symptoms for prehypertension or hypertension, making it imperative to get regular screening.What you can do: The American Heart Association recommends getting your blood pressure checked at least every two years—even if your blood pressure is usually normal. If you have diabetes or a family history of highbloodpressure, or are overweight, inactive or a smoker, your doctor may recommend more frequent checks. An annual physical will always include a blood pressure check, which is an ideal way to stay on top of your numbers. Amy Epps, MD, FACC, a cardiologist in private practice in Columbia, South Carolina, says that "just a little diet modification—eating a balanced diet and watching your salt intake—and starting an exercise regimen might help lower your blood pressure and minimize your risk of developing hypertension and heart disease." According to the American Heart Association, managing stress levels, limiting alcohol and stopping smoking can also facilitate healthier blood pressure. Photo: Thinkstock

Cervical Dysplasia

What it is: Cervical dysplasia means there is the presence of abnormal cells on the cervix, which may be a precursor to cervical cancer. Most cases of cervical dysplasia occur between the ages of 25 and 35, although it can be present at any age. A Pap smear can detect cervical dysplasia, and categorizes it as low-grade, high-grade or possibly cancerous. The main cause is high-risk strains of human papillomavirus (HPV), a virus that is sexually transmitted. "There are other factors that are involved, but HPV is found in well over 90 percent of cervical cancers," says Allison Blazek, MD, a private practice internist in Houston. In addition to HPV, other factors can increase a woman's chance of cervical cancer, including multiple sexual partners, a history of STDs, a weakened immune system and smoking. Typically, there are no symptoms of precancerous cervical changes. However, bleeding during or after sex can occur if cervical cancer is present.What you can do: Being in a mutually monogamous relationship with someone who does not have HPV or limiting your number of sexual partners and using condoms can all help prevent you from contracting the virus. Screening is essential for all ages (find the National Institutes of Health guidelines here). Depending on the level of dysplasia and your age, Pap smears may be performed up to every six months to monitor the cells, or treatment may be provided in the form of advanced testing and removal of the cells from the cervix, which can be done via cone biopsy (in which a small cone-shaped area containing precancerous cells is removed), Loop Electrosurgical Excision Procedure (in which an electrically charged wire scoops out abnormal cells), cryotherapy to freeze the cells, or laser removal. If precancerous changes are found, it does not necessarily mean that a cervical cancer diagnosis is coming soon, however. "It can take 10 to 20 years for the cancer to form," Dr. Blazek says. Photo: Science Photo Library/Getty Images

Pre-Diabetes

What it is: Blood sugar levels above the normal range (find the range guidelines here) indicate pre-diabetes, which can develop into type 2 diabetes within 10 years. Diabetes occurs when the body lacks the mechanism to produce enough insulin to convert food into energy. "There aren't always symptoms of pre-diabetes or diabetes, which is why so many people don't realize they have it," says Janis Roszler, RD, CDE, LD/N, author of Diabetes on Your Own Terms. When there are symptoms—which may include excessive thirst or hunger, fatigue, a tingling sensation in the feet and frequent urination—many people do not notice them or mistake them for signs of other things. Two different tests can confirm pre-diabetes and diabetes: an oral glucose tolerance test and a fasting plasma glucose test. (There is a a newer test available, an A1C blood test, which measures your blood sugar for the past two to three months. However, it is used to diagnose and monitor diabetes.)What you can do: Testing for diabetes should be done every three years for anyone over 45. Earlier testing is recommended for those who are overweight or inactive, have high blood pressure and/or cholesterol, a family history of diabetes, a history of gestational diabetes (or have given birth to a baby larger than 9 pounds) or a history of polycystic ovary syndrome, and those of African-American, Latino, Asian or Native American descent. People with pre-diabetes should be tested every one to two years to make sure the condition has not progressed. Staving off the onset of diabetes is highly possible with certain lifestyle adjustments. "If you become more active and lose just 5 to 10 percent of your body weight, it's possible to slow down pre-diabetes and delay the progression to diabetes or prevent it altogether," Roszler says. Performing 30 minutes of moderate exercise—even just walking—five days a week has been shown to have a tremendous benefit. For nutrition, it is best to keep saturated fat and cholesterol to a minimum, as well as refined sugars and heavy starches; instead, opt for lean meat and vegetables as much as possible. Photo: Shutterstock

Osteopenia

What it is: Osteopenia is low bone mass, a condition in which bones are brittle and easily fractured, which can lead to osteoporosis. Osteopenia and osteoporosis are "silent" diseases, says Raymond Cole, DO, PC, clinical assistant professor in the department of internal medicine at Michigan State University College of Osteopathic Medicine. "Most women don't know they have osteopenia or osteoporosis until they fracture a bone," Dr. Cole says. To confirm the presence of either condition, a bone mineral density (BMD) test—a scan that details the amount of bone mass density in the hips and/or spine—should be performed. By and large, this test is given to postmenopausal women, as they are most affected by osteopenia and osteoporosis. "After menopause, there is no longer the protective effect of estrogen on the bone, and therefore bone loss accelerates by about 3 to 5 percent a year for the next five to seven years," Dr. Cole explains.What you can do: Postmenopausal women should undergo a BMD test every one to two years. Premenopausal women should be tested if they have risk factors for osteoporosis, which include low body weight, low calcium intake, excessive alcohol or caffeine consumption, lack of exercise, smoking and/or a family history of osteoporosis, and Caucasian or Asian descent. If you are diagnosed with osteopenia, there are steps you can take to slow down or stave off bone loss and risk of fractures. Dr. Cole recommends starting with increasing calcium intake. The National Osteoporosis Foundation recommends that women under 50 consume 1,000mg of calcium per day (via food and, if needed, supplements); women over 50 should consume 1,200mg per day. According to The Journal of the American Medical Association, other habits that can help include increasing your intake of vitamin D (expose your skin to sunlight for 10 minutes a day and/or consume vitamin D–fortified foods), exercising regularly (particularly doing weight-bearing exercise, such as walking) and eliminating risk factors such as smoking and excessive alcohol consumption.Photo: Shutterstock

Colon Polyps

What it is: Colon polyps are small growths that develop in the colon and rectum. "If a colon polyp is left untreated for an estimated 8 to 12 years, it can transform into cancer," says Patricia Raymond, MD, FACP, FACG, a gastroenterologist in Chesapeake, Virginia. "Most people with polyps have no symptoms," says Dr. Raymond, adding that those with colon cancer often have no symptoms either. There are four types of tests that can determine if you have colorectal polyps and/or cancer: a flexible sigmoidoscopy, in which a small lighted tube with a video camera is used to view the rectum and lower colon; a colonoscopy, featuring a longer sigmoidoscope-like device to view the entire colon; a double-contrast barium enema, which is a type of X-ray test; and a CT colonography, which is essentially a CAT scan of the colon and rectum. If polyps are detected during a sigmoidoscopy or colonoscopy, they are usually removed or biopsied and tested for cancer.What you can do: Lifestyle changes can help prevent colon polyps and colon cancer, including getting regular exercise, eating a healthy diet featuring fresh fruits and vegetables and lean meats, not smoking and getting adequate sleep. For those of average risk, a colonoscopy should be performed every 10 years beginning at age 50; Dr. Raymond recommends African-Americans of average risk begin getting tested at age 45. For people of increased or high risk, screening should be performed earlier and more often, as directed by your doctor. A number of factors can lead to a heightened risk of colon polyps, including a personal or family history of colorectal polyps and/or cancer, inflammatory bowel disease, an inherited colorectal cancer syndrome and lifestyle factors such as a diet high in red and processed meats, obesity, a lack of physical activity, smoking, heavy alcohol use and type 2 diabetes. The greatest risk is for those over the age of 50 as well as African-Americans and Jewish people of Eastern European descent. Photo: Shutterstock